First I tried to install debian. That did not Work at all. For some reason the screen never showed annything, so I tried the installation on arch. The installation on a microsd card worked like a charm, so, for a while I ran off that, however it was slow. tying to dd the micro sd card installation to the emmc did not work, so I looked around. Keenerd (lots of thanks to him) had gave the hint to rerun the installer on the chromebook with the emmc as target. that worked like a charm.
He also gave some configuration hints, that were really helpfull, however the xf86-video-armsoc-rockchip did not work for me, however after removing it and using just the xserve-Xorg-video-fdbev (preinstalled) does work like a charm (I will never be able to play significant games on it annyway).
To enable audio run
amixer -c 0 sset “Right Speaker Mixer Right DAC” unmute
amixer -c 0 sset “Left Speaker Mixer Left DAC” unmute
sudo alsactl store
that will enable sound somehow (I still only have sound from one youtube instance, but for me that is ok)